Closes#1856

Pure API updates:

• Add classDice
• AddBot.send_dice
• AddMessage.dice
• AddMessage.reply_dice
• Add classBotCommand
• AddBot.get_my_commands
• AddBot.set_my_commands
• AddBot.commands property
• Add parametertgs_sticker toBot.create_new_sticker_set
• Add parametertgs_sticker toBot.add_sticker_to_set
• AddStickerSet.thumb
• AddBot.set_sticker_set_thumb
• Tests
• Add warning about changed parameter order forBot.create_new_sticker_set andBot.add_sticker_to_set to release notes

New functionality:

• AddFilters.dice to filter messages containing a dice
• AllowFilters.dice(1) andFilters.dice([1, 5]) to filters for dices with specific values
• Somehow allow to treat a dice message as text message with the corresponding emoji viaFilters.text andMessage.effective_message?
• Tests

Problems I encountered:

• I didn't have the means to nor did I feel like creating a custom animated sticker for testing purposes. So I just downloaded one vie TG desktop. Copyright concerns?
• Bot.create_new_sticker_set was not tested before, I guess because we can't delete packs via the API. So I don't test with the new parameter, either.
• Bot.upload_sticker_file seems to accept TGS files aspng_sticker. I'm jusing it ittest_bot_methods_1_tgs right now. Also pinged@botsupport about it. The resultingfile_id is not valid
• While improving coverage I noticed, that themask_position foradd_sticker_to_set was untested. If I see correctly, request posts differently when posting files, which is the case for stickers, and thus themask_position has to beto_json-ed manually. Added that and the corresponding test.